High powered, long stroke linear actuators as generally known in the art involve use of solid-state thrusters, motors, self-activating clutches and compliant gearing. Such actuators are disclosed for example in U.S. Pat. Nos. 5,705,863 and 6,294,849, featuring methods of enhancing operation of a magnetostrictive type of motor to minimize and limit stroke impact.
Because hydraulic cylinder type linear actuators heretofore utilized have a low power density, attempts have been made to replace such hydraulic actuators with electromechanical types of linear actuators with higher power density without success because of reliability and scaling problems with power screws. Controllability problems have also occurred with respect to the clutch units associated with linear actuators, while stroke limiting problems were heretofore associated with the use of solid-state thrusters in such linear actuators. It is therefore an important object of the present invention to provide a linear force applying actuator involving the beneficial use of electric magnetostrictive types of motors and solid-state thrusters with clutch units having associated facilities to deal with load inertia and control stroke while avoiding the other aforementioned problems heretofore associated with linear actuators.